A multilayer ceramic capacitor as an example of multilayer ceramic electronic devices is produced by alternately stacking, for example, ceramic green sheets and internal electrode layers having a predetermined pattern, then making the same one body to obtain a green chip and simultaneously firing the green chip.
The internal electrode layers of the multilayer ceramic capacitor as above are made to be one body with ceramic dielectrics by firing, so it has been necessary to select materials not reacting with ceramic dielectrics.
Conventionally, platinum, palladium and other precious metals have been used as materials for composing internal electrode layers. However, since precious metals are expensive, it has been a cause of high costs of produced capacitors.
While, in recent years, it became possible to use nickel and other inexpensive base metals as materials composing internal electrodes and a wide reduction of the costs has realized.
Conventionally, a variety of proposals have made on dielectric ceramic compositions wherein an inexpensive base metal can be used as a material of internal electrodes. For example, in the Japanese Unexamined Patent Publication No. 6-45182, a dielectric ceramic composition wherein a dielectric oxide (note that 0≦x≦0.25, 0≦y≦0.05, 0.1≦z≦0.3, 1.000≦m≦1.020) indicated by a composition formula [(Ba1-x-yCaxSry)O]m(Ti1-zZrz)O2 is a main component is disclosed. In the Japanese Unexamined Patent Publication No. 6-342735, a dielectric ceramic composition wherein BaTiO3 is a main component is disclosed. In the Japanese Unexamined Patent Publication No. 10-335169, a dielectric ceramic composition wherein a dielectric oxide (note that 0≦x≦1.00, 0.9≦y≦1.00, 0.75≦m≦1.04) indicated by a composition formula (Sr1-xCax)m(Ti1-yZry)O3 is a main component is disclosed.
On the other hand, along with electronic devices getting more compact in recent years, a more compact and larger capacity multilayer ceramic capacitor has been demanded. To realize a more compact larger capacity multilayer ceramic capacitor, it is necessary to make a thickness of one dielectric layer as thin as possible and to increase the number of layers to be stacked in a predetermined size as much as possible (stacking more layers).
However, as dielectric layers get thinner and stacked more, a shape of an obtained ceramic capacitor is liable to cause anisotropy. When anisotropy arises in a shape of a capacitor, tractability at the time of mounting the capacitor on a substrate, etc. declines.
Also, as dielectric layers get thinner and stacked more, electric characteristics, such as static capacitance and insulation resistance, have been also liable to decline.
Furthermore, as dielectric layers get thinner and stacked more, cracks (particularly, inner cracks) have been liable to occur in an obtained capacitor. When a crack arises inside a capacitor, it cannot endure to be used as a capacitor.